Mouth and throat problems

Radiation therapy is often used to treat cancer in the mouth, throat, neck or upper chest region. Depending on the area treated, radiation therapy may affect your mouth and teeth. This can make eating and swallowing difficult and change your sense of taste.

Treatment to the mouth may increase the chance of tooth decay or other problems in the future. You will need to have a dental checkup before treatment starts and regular check-ups after it finishes.

If you’re seeing a dental specialist, such as an orthodontist, ask if they can liaise with your usual dentist about any work you need to have before radiation therapy starts. Your dentist can give you detailed instructions about caring for your mouth to help prevent tooth decay and deal with side effects such as mouth sores.

Learn more about:

Dryness and other issues

After several weeks of treatment, your mouth or throat may become dry and sore, and your voice may become hoarse. Radiation therapy can affect your salivary glands so you produce less saliva, which can contribute to the dry mouth. These effects will gradually improve after treatment finishes, but it may take several weeks or even months. In some cases, the effects may improve but not completely disappear.

You may have thick phlegm in your throat, or a lump-like feeling that makes it hard to swallow. Food may also taste different. Taste changes may last for many months after treatment, but normal taste usually returns eventually.

Tips for managing mouth and throat problems

  • If possible, have a dental check-up before treatment begins with a dentist who specialises in the effect radiation therapy has on teeth.
  • Keep your mouth moist by sucking on ice chips and sipping cool drinks. Carry a bottle of water with you.
  • Ask your doctor, nurse or pharmacist for information about artificial saliva to moisten your mouth.
  • Avoid tobacco and alcohol, as they will irritate your mouth and make dryness worse.
  • If chewing and swallowing are painful, try to consume more liquids or soft food. Talk to a dietitian, who can suggest nourishing foods that will not hurt your mouth.
  • If you have trouble swallowing, ask your doctor for a referral to a speech pathologist.
  • To manage taste changes, try different ways of preparing food. For example, add lemon juice to meat and vegetables, marinate foods or add spices.
  • Talk to your doctor if eating is uncomfortable or difficult. If you are in pain, ask for pain medicine, which may help with swallowing.
  • Rinse your mouth regularly using an alcohol-free mouthwash recommended by your doctor or dentist. Saltwater is a natural disinfectant – you can make a saltwater mouthwash at home by dissolving ¼ teaspoon of salt into 1 cup of warm water. Rinse your mouth with plain water afterwards.
  • For more on this, call 13 11 20 or see Mouth Health and Cancer Treatment.

This information was last reviewed in December 2017
View who reviewed this content
View our editorial policy

Support services

Coping with cancer?
Ask a health professional or someone who’s been there, or find a support group or forum

Need legal and financial assistance?
Pro bono legal and financial matters, no interest loans or help with small business

Work and cancer
Information for employees, employers and workplaces dealing with cancer

Cancer information

Mouth health and cancer treatment
Here we look at the side effects of chemotherapy, radiation therapy and surgery or a combination of treatments that affect the mouth area.


Managing cancer side effects
Cancer and cancer treatments may cause a range of side effects. They vary depending on the treatments you were given. Learn more.

View our publications
Guides and fact sheets for people with cancer, their families and friends